1. Field of the Invention
The present invention concerns a disk drive, and more particularly to a technique for measuring the position error signal of a disk drive.
2. Description of the Related Art
Generally a position error signal (hereinafter referred to as a "PES") obtained by detecting a burst is valued by the resolution of an A-D converter, including the maximum and minimum values. Therefore, the percentages of PES are not determined by the width of the track, but are determined by an absolute value (constant) peculiar to the resolution of an A-D converter. Normally the width of the track may vary with the head margin, characteristics of the recording margin, servo write, etc., so that the correctness of the percentages of PES may not be secured if the width of the track varies with the apparatus, circuits or external environment.
The following patents each disclose features in common with the present invention but do not teach or suggest the specifically recited technique for measuring the position error signal of a disk drive in accordance with the present invention: U.S. Pat. No. 5,576,906 to Fisher et aL, entitled Synchronous Detection Of Concurrent Servo Bursts For Fine Head Position In Disk Drive, U.S. Pat. No. 5,576,910 to Romano et al., entitled Burst Comparison And Sequential Technique For Determining Servo Control In A Mass Storage Disk Device, U.S. Pat. No. 5,602,692 to Freitas et al., entitled Sampled Position Error Signal Demodulation System For Banded Data Disk Drives, U.S. Pat. No. 5,602,693 to Brunnett et al., entitled Method And Apparatus For Sensing Position In A Disk Drive, U.S. Pat. No. 5,615,058 to Chainer et aL, entitled Method And System For Writing A Servo-Pattern On A Storage Medium, U.S. Pat. No. 5,453,887 to Negishi et al., entitled Head Tracking Servo Pattern, and U.S. Pat. No. 5,381,281 to Shrinkle et al., entitled Disk Drive System Using Multiple Embedded Quadrature Servo Fields.